WPF DataGrid复选框列样式

Question

I want to create a datagrid with (M x N) cells. Each cell shall contain a Checkbox. Now if the checkbox of one cell is selected, I want to change the background color of this specific cell to red.

My problem is that I don't know how many rows and columns will be there at runtime.

Can someone please help me with a little example? Or give me a hint where to start? I searched the web for days now without any success :(

Thank's!

Sebastian

Answer 1

You could create types that represents a row and a cell and create some cell templates and cell styles programmatically in the view. Please refer to the following example.

public class Row
{
    public Cell[] Cells { get; set; }
}

public class Cell : INotifyPropertyChanged
{
    private bool _isChecked;
    public bool IsChecked
    {
        get { return _isChecked; }
        set { _isChecked = value; NotifyPropertyChanged(); }
    }


    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "") =>
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

public class ViewModel
{
    public ViewModel()
    {
        const int n = 10;
        const int m = 5;

        List<Row> rows = new List<Row>();
        for (int i = 0; i < n; ++i)
        {
            rows.Add(new Row { Cells = new Cell[m] });
            for (int j = 0; j < m; ++j)
            {
                rows[i].Cells[j] = new Cell();
            }
        }
        Rows = rows;
    }

    public IEnumerable<Row> Rows { get; set; }
}

View:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        Window2ViewModel viewModel = new Window2ViewModel();
        Row row = viewModel.Rows.FirstOrDefault();
        if (row != null)
        {
            DataTemplate dataTemplate = dataGrid.Resources["cellTemplate"] as DataTemplate;
            for (int i = 0; i < row.Cells.Length; ++i)
                dataGrid.Columns.Add(new DataGridTemplateColumn() { CellTemplate = CreateCellTemplate(i), CellStyle = CreateCellStyle(i) });
        }
        DataContext = viewModel;
    }

    private static DataTemplate CreateCellTemplate(int index)
    {
        const string Xaml = " <DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\" x:Key=\"cellTemplate\"><CheckBox IsChecked=\"{{Binding Cells[{0}].IsChecked, UpdateSourceTrigger=PropertyChanged}}\" Content=\"Check\" /></DataTemplate>";
        return XamlReader.Parse(string.Format(Xaml, index)) as DataTemplate;
    }

    private static Style CreateCellStyle(int index)
    {
        const string Xaml = "<Style TargetType=\"DataGridCell\" xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\"> " +
                            "     <Style.Triggers> " +
                            "       <DataTrigger Binding=\"{{Binding Cells[{0}].IsChecked}}\" Value=\"True\"> " +
                            "        <Setter Property=\"Background\" Value=\"Red\" /> " +
                            "       </DataTrigger> " +
                            "     </Style.Triggers> " +
                            "</Style>";

        return XamlReader.Parse(string.Format(Xaml, index)) as Style;
    }
}

XAML:

<DataGrid x:Name="dataGrid" ItemsSource="{Binding Rows}" AutoGenerateColumns="False" CanUserAddRows="False" />

Answer 2

This example is not finished yet but demonstrates how I solved it now:

This example is not using a DataGrid. And the layout s*cks :D

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        List<KeyGroup> keygroups = new List<KeyGroup>();
        ColumnHeaderRow headerrow = new ColumnHeaderRow(keygroups);
        for (int i = 0; i <= 10; i++)
        {
            keygroups.Add(new KeyGroup("Col " + i.ToString()));
        }

        VStack.Children.Add(headerrow);

        for (int i = 0; i <= 10; i++){
            List<CellObject> cells = new List<CellObject>();
            for (int j = 0; j <= 10; j++)
            {
                if (i % 2 == 0) cells.Add(new CellObject(i, j, true));
                else cells.Add(new CellObject(i, j, false));
            }
            RowObject newrow = new RowObject(cells);
            VStack.Children.Add(newrow);
        }
    }
}

public class RowObject : StackPanel
{
    public List<CellObject> cells { get; set; }

    public RowObject(List<CellObject> cells)
    {
        this.cells = cells;
        this.Orientation = Orientation.Horizontal;
        foreach(CellObject cell in this.cells)
        {
            this.Children.Add(cell);
        }
    }
}

public class CellObject : CheckBox
{
    public int Row { get; set; }
    public int Column { get; set; }
    public Int64 Id { get; set; }
    public bool Value { get { return this.IsChecked.Value; } set { this.IsChecked = value; } }
    public Int64 IdLck { get; set; }
    public Int64 IdKey { get; set; }
    public SolidColorBrush BackgroundColor { get; set; }


    public CellObject(int row, int column, bool value)
    {
        this.Value = value;
        this.Row = row;
        this.Column = column;

        this.Checked += OnChecked;
        this.Unchecked += OnUnchecked;

        if (this.Value)
        {
            this.Background = new SolidColorBrush(Colors.Red);
            this.Foreground = new SolidColorBrush(Colors.Green);

        }
    }

    private void OnUnchecked(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("You unchecked Row: " + this.Row.ToString() + " Column: " + this.Column.ToString());
    }

    private void OnChecked(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("You checked Row: " + this.Row.ToString() + " Column: " + this.Column.ToString());
    }
}

public class KeyGroup
{
    public String Name { get; set; }

    public KeyGroup(String name)
    {
        this.Name = name;
    }
}

public class ColumnHeaderRow : StackPanel
{
    public ColumnHeaderRow(List<KeyGroup> keygroups)
    {
        this.Orientation = Orientation.Horizontal;

        foreach (KeyGroup kg in keygroups)
        {
            TextBox tb = new TextBox();
            tb.Text = kg.Name;
            this.Children.Add(tb);
        }
    }
}